1. Field of the Invention
The present invention relates to television systems.
2. Background Art
Improvements in television (TV) technologies over the past half century have facilitated the development of different systems for providing TV signals.
In addition to broadcast TV systems, such systems include community antenna TV (CATV) systems (i.e., cable TV) and direct-to-home (DTH) TV systems (i.e., satellite TV). Providers of broadcast and DTH TV signals must contend with the locations and the widths of the bands of frequencies in the electromagnetic spectrum that have been allocated to them by the United States Federal Communications Commission (FCC). Providers of CATV signals, which typically are conveyed via transmission lines, such as coaxial cables, can be limited by the lowpass filter characteristics of the transmission lines. For these reasons, the different systems generally operate over different bands of frequencies.
Advancements in TV technologies have also facilitated the development of additional services that can be rendered via TV systems. Such services include, but are not limited to, more channels for TV programs, video on demand, and Internet communications. However, the ability to provide simultaneously several of these services to a user can be constrained by the widths of the bands of frequencies that are available for (e.g., assigned by the FCC) or capable of (e.g., the lowpass filter characteristics of transmission lines) providing TV signals. Because of these frequency constraints, expanding the number of services that TV systems can simultaneously provide depends upon an ability to increase the amount of data that can be transmitted within the given bands of frequencies. Thus, there is a need to increase the amount of data that can be transmitted within the given bands of frequencies.